Light microscopic autoradiographic studies were made on the distribution of ¹⁴C-1, 2-dimethylhydrazine dihydrochloride in Swiss mice and on the effect of 1, 2-dimethylhydrazine dihydrochloride on DNA synthesis, using the ³H-thymidine incorporation technique. In the first study, ¹⁴C-1, 2-dimethylhydrazine dihydrochloride was administered subcutaneously or orally. Large amount of silver grains were found in hepatocytes and substantially lower amount of silver grains observed in the endothelial cells and epithelial cells of colon. In the second study, repeated injections or oral administrations of 1, 2-dimethylhydrazine dihydrochloride were given to mice which subsequently received ³H-thymidine treatment. A somewhat higher amount of thymidine incorporation in DNA was noted in the epithelial cells of the colon of subcutaneously and orally treated mice at two occasions and a substantially higher amount in the endothelial cells of blood vessels in liver of mice treated by both routes than in the corresponding controls. In three instances, however, the amount of incorporation decreased; in the hepatocytes and endothelium at 1 week and 24hr, respectively, after oral treatment, and in the epithelium of the colon at 3 months, after subcutaneous administration.
In the mice treated with 1, 2-dimethylhydrazine dihydrochloride, a significantly high amount of ³H-thymidine incorporation was observed in the endothelial cells of blood vessel in liver from which tumors later arose, and somewhat high in the hepatocytes in which tumor did not develop. In the epithelial cells of colon, no apparent relationship can be seen between these events. No association was seen in the distribution of ¹⁴C-1, 2-dimethylhydrazine dihydrochloride and tumor development in various cells.

View full abstract

A dose of 10 or 20mg of N-butylnitrosourea (BNU) dissolved in 50% ethanol was administered by a gastric tube to 6-week-old male ICR/JCL strain mice and they were sacrificed 15 months later. One of 18 animals developed a hepatoma, but none of the mice given CCl₄ in 0.1ml of 50% olive oil subcutaneously at the right thigh developed hepatoma. However, a marked enhancement of hepatoma induction was observed in mice injected with CCl₄, one day before the single intragastric administration of BNU, with 12 out of 28 mice developing one or more hepatomas (average 3.2/mouse) ranging in diameter from 0.5 to 1.5cm. By extending the administration interval between CCl₄ and BNU to 1 week or 1 month, or by reversing the order of administration, the hepatotumorigenic action was virtually lost. There was no occurrence of hepatoma but a predominant development of leukemia, of either thymic or nonthymic origin, was observed in mice of younger age treated with CCl₄ one day before continuous oral administration of BNU (1mg/day/mouse). It is thus concluded that the preparative (cocarcinogenic) action of CCl₄ is indispensable for hepatotumorigenesis with a single large dose of BNU.

View full abstract

Carcinogenic effect of a single oral administration of 300 or 200mg/kg body weight of 1-butyl-1-nitrosourea (BNU) and continuous oral administration of 400ppm solution of BNU in the drinking water for 5, 10, 15, and 20 weeks to female SD rats was studied. In addition, the number of spleen cells capable of forming plaques (PFC) against primary immunization with sheep red blood cells was investigated in various stages of the animal experiments.
With a single oral administration of BNU, tumors developed in 31/50 (62%) rats between the 25th and 75th week. They were most frequently seen in the mammary gland (40%), followed by the stomach (10%), kidneys (8%), and ovary (8%). Leukemia was found in 8%. No dose-effect relationship was observed in these 2 experimental groups.
On the other hand, tumors developed in 67/77 (88%) of the rats that received BNU in their drinking water. The incidence of tumors was highest in leukemia (61%), followed by mammary tumors (26%), intestinal tumors (12%), and ear duct tumors (8%). There was a dose-effect relationship among the 4 groups in the latent period and target organs for tumor development.
Although the PFC count of the rats receiving BNU for 5 weeks recovered gradually to about 50% of the control level at the end of the 25th experimental week, it remained less than 10% of the control level for the whole experimental period in those receiving BNU longer than 10 weeks. Therefore, it was apparent that the tumors developed, proliferated, and finally killed the host rats in highly immunosuppressive state.

View full abstract

The occurrence of benign tumors and diverticula of the digestive tract was investigated in an autopsy study of a fixed population of 100, 000 samples in Hiroshima and Nagasaki. There were 664 benign tumors and 40 diverticula. Polyps were the most frequent tumor, were found more often in older people, occurred as single pedunculated well-differentiated adenomatous tumors, and most were less than 5mm in greatest dimension. Larger polyps tended to have more atypism, but none showed definite premalignant change. No transition from benign to malignant polyps was seen. Polyps were found most frequently in the large intestine and in a large number (21%) and, when cancer of the large intestine was present, benign polyps were also found. Far more polyps are found when special intensive search is made for them. Comparison of the occurrence of benign polyps in different geographic areas must be adjusted for age and method of search as well as for other features such as histological type, dysplasia, etc. There was no evidence that the occurrence of benign tumors or diverticula was related to prior exposure to ionizing radiation.

View full abstract

The effect of syngeneic tumor cell mixed with BCG on intradermal tumor growth and on specific tumor immunity was evaluated. (1) With the use of several early transplant generations of syngeneic mouse tumors, the ratio of 1:10 to 1:20 of tumor cell-BCG was confirmed as the best for the present mousetumor system. (2) The development of immunity capable of eradicating distant tumor deposit was tested by varying doses of tumor deposit inoculated at the same time as the mixture of tumor cell-BCG. The remarkable efficacy of the tumor cell-BCG mixture on local tumor suppression (7/8) and tumor immunity (5/7) was proved with tumor burden of 10⁵ cells or less. Control mice receiving BCG contralateral to the tumor site (10⁵) were not able to achieve tumor immunity (1/8), but were able to reject the local tumor (8/8). (3) The tumor cell-BCG mixture was as effective in a line of rat lung carcinoma as it was in the mouse system in rejecting both the local tumor and the tumor challenge injected intramuscularly. (4) Intratumor injection of BCG or nonliving BCG preparation (in which whole cell wall of BCG is attached to oil droplets) in primary tumors in mice previously sensitized with BCG led to a few instances of complete tumor regression in animals having tumor nodules of 3 to 10mm in diameter. The survival period of animals treated with BCG or with nonliving BCG preparation was significantly longer than that of saline-treated controls.

View full abstract

The skin response to 5μg of purified phytohemagglutinin (PHA) was studied in 299 subjects, including 58 normal controls, 92 patients without malignancies, and 149 patients with nonlymphomatous cancer. Other immunological responses, such as in vitro lymphocyte stimulation (62 subjects) and skin response to purified protein derivatives (PPD) (95 subjects), were tested simultaneously to examine their correlation with the PHA skin test. A positive reaction was observed 24hr after intradermal injection of 5μg of purified PHA in 56 (96.6%) of 58 normal controls, 40 (49.4%) of 81 untreated patients with cancer, and 24 (35.3%) of 68 cancer patients receiving anticancer therapy. Among 32 patients with gastric cancer tested, impaired skin reactivity to purified PHA was noted in patients in stage III or IV. A correlation was found between in vivo and in vitro responses to PHA in 46 (74.2%) of 62 individuals (P<0.001), and between PHA and PPD skin responses in 68 (71.6%) of 95 cancer patients (P<0.01). The PHA skin test was repeated 4 times over a period of three months in patients without malignancies, and no significant change in their skin reactivity was detected. In repeated tests, the skin reactivity to purified PHA of patients with lung cancer varied depending on the clinical status, and the extent and type of anticancer therapy the patients were receiving. It is concluded that the PHA skin test is a simple diagnostic method for screening for immunodeficiency in cancer patients before and during the course of anticancer therapy. Other advantages of this test are that no presensitization is required and that it can be used repeatedly.

View full abstract

Effect of PS-K on tumor growth and antibody production was studied in inbred C57BL/6, SL, C3H/He, and AKR mice, and in colony-bred ICR mice. (1) PS-K exhibited antitumor activity on sarcoma-180 in ICR mice, but not in AKR mice. Growth of sarcoma-180 was suppressed to the intermediate extent in other strains. (2) In ICR strain, antibody production against trinitrophenyl was depressed in mice bearing sarcoma-180 and restored by PS-K. In AKR mice, on the other hand, antibody production was not depressed in tumor-bearing state and was not augmented by PS-K. Other strains showed intermediate degrees of suppression of antibody-producing capacity by sarcoma-180 and its restoration by PS-K. (3) In ICR strain, the growth of Ehrlich tumor as the challenge tumor was enhanced in mice bearing sarcoma-180 as compared to that in controls. After the treatment with PS-K in this strain, however, not only the growth of sarcoma-180 but also of Ehrlich tumor was inhibited completely. On the other hand, the growth of Ehrlich tumor in AKR strain was neither enhanced in mice bearing sarcoma-180 nor inhibited by PS-K.

View full abstract

Synergistic effects of sulfur-containing purines and related ribonucleosides (6-thioinosine, 6-thioguanine, 6-thiocyanatopurine, 6-methylthioinosine, 6-thiocyanatoguanine, 6-thiocyanatoguanosine, 6-phenacylthioinosine, 6-nitrobenzylthioinosine, 6-(p-chlorobenzyl)thioinosine, 6-(p-nitrobenzyl)thioguanosine, 6-benzylthioinosine, 6-ethylthioinosine, 6-benzylthioguanine, 6-benzylthiopurine, 6-methylthiopurine, and 6-thiocyanatoinosine) and chlorine-containing purine and its ribonucleoside, (6-chloropurine and 6-chloropurine riboside), in combination with the polyene antibiotic, Amphotericin-B, on cell survival and synthesis of DNA were examined in mouse leukemia L5178Y cells. 6-Methylthioinosine, 6-thiocyanatopurine, 6-thiocyanatoinosine, 6-methylthiopurine, and 6-thiocyanatoguanine (or -guanosine) among sulfur-containing compounds were strongly potentiated by Amphotericin-B, and 6-chloropurine riboside, which is electronically analogous to methylthioinosine, was also enhanced by the polyene. Thiocyanoto or methylthio group at position 6 of the purine ring seems to be important for the polyene-mediated potentiation. 6-Methylthioinosine alone had much greater effect on DNA synthesis of HeLa cells than on L5178Y cells, and Amphotericin-B failed to potentiate the action of 6-methylthioinosine in HeLa cells.

View full abstract

The response of normal cerebral tissue of dogs to boron-neutron capture therapy by the currently available improved method was studied by electron microscopy. Peripheral blood capillaries of the neutron-irradiated area in the left cerebral hemisphere were compared with their counterparts in the shielded and non-irradiated right hemisphere. No ultrastructural changes, as those noted in classical method of boron-neutron capture therapy, were found in endothelial cells and their surroundings after neutron irradiation by the improved technique of boron-neutron capture therapy. There was no swelling of endothelial cells, disappearance of cristae of mitochondria, increased pinocytosis, disappearance of ribosomes, enlargement of Golgi apparatus, or increased appearance of endoplasmic reticulum. Basement membrane was not disrupted and was uniform. Pericytes, synaptosomes, and other glial elements remained intact.
In contrast to the old clinical trials up to 1961, the renewed boron-neutron capture therapy is regarded not to cause serious damage to the central nervous system.

View full abstract

Antitumor activity of 1-carbamoyl derivatives of 5-fluorouracil was tested in L-1210 system by oral administration with two reference compounds, 5-fluorouracil and tetrahydrofuryl-5-fluorouracil (FT-207). The compounds tested were methyl-, ethyl-, isopropyl-, phenyl-, and cyclohexyl-carbamoyl-5-fluorouracil, and the therapeutic ratios (ILS_max/ILS₃₀) of these compounds were 1.9, 2.2, 2.3, 1.0, and>3.3, respectively, those of the two reference compounds being 1.7 and 1.0. Cyclohexylcarbamoyl-5-fluorouracil was the most effective of these compounds.

View full abstract

Streptococcal preparation, OK-432, was examined for its ability to initiate a host-mediated immune response. Aged individuals with negative skin response to phytohemagglutinin (PHA), as well as reduced in vitro blastoid transformation of lymphocytes, were treated with OK-432, and the response to PHA appeared in two out of three cases. The preparation was also demonstrated to convert C3 proactivator of complement when incubated with fresh human serum, as tested by immunoelectrophoresis, indicating the possibility that OK-432 might activate the alternate pathway of complement.

View full abstract

The protein-bound polysaccharide preparation, PS-K, was found to possess an antitumor effect against 3-methylcholanthrene-induced fibrosarcoma in mice which was shown to have a tumor-specific transplantation antigen. This antitumor effect seemed to be exerted through a host-mediated tumor immunity.

View full abstract

The experimental induction of gastric cancer was studied in four dogs given oral administration of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) in solution. Esophageal cancer with the regional lymph node metastasis was found in one dog at autopsy, with concomitantly existing gastric cancer. This dog, which ingested a total amount of about 38g of ENNG, died of weakness on the 513th experimental day. Three remaining dogs are still living and under observation.

View full abstract

The relation between the histological type and the presence of estrogen receptor or response to oophorectomy was investigated in the mammary cancer induced by 7, 12-dimethylbenz[a]anthracene in Sprague-Dawley rats. The estrogen receptor was present in 75.0% (3/4) of poorly differentiated cancer and in 62.5% (10/16) of well-differentiated cancer. The histological degree of differentiation or grading of the rat mammary cancer did not affect the presence of the estrogen receptor or response to oophorectomy. In contrast, there was clearly a good correlation between the presence of the receptor and response to oophorectomy.

View full abstract

Electron microscopic examination on three lines of transplantable reticulum cell sarcomas, induced spontaneously in the mesenteric lymph nodes of inbred strain ACI rats, proved the presence of intracisternal A particles in all the three tumor lines. The doughnut-shaped particles measured 50 to 70nm and were seen to bud from the membranes of rough-surfaced endoplasmic reticulum. Frequency of appearance of these particles varied with the tumor line.

View full abstract

The loss of mitochondrial DNA was found in a cytoplasmic respirationdeficient mutant of yeast, strain N-1, induced by treatment of a normal yeast with 4-nitroquinoline 1-oxide. In cesium chloride density gradient centrifugation, mitochondrial DNA from the normal yeast showed a density of 1.684g/ml, but mitochondrial fraction of respiration-deficient mutant strain N-1 had no detectable DNA at a density of 1.684g/ml or near it. Though an incorporation of 3H-adenine into mitochondrial DNA was amplified by the presence of cycloheximide, the mutant had no detectable radioactivity in its mitochondrial fraction. Accordingly, it was concluded that respiration-deficient mutant strain N-1 has lost its mitochondrial DNA which was indispensable for the respiratory activity of yeast cells.

View full abstract

Investigations were carried out with cultured mammalian cell lines to assess the effect of combination of radiation and Bleomycin. When cells were treated with the antibiotic before and during exposure to X-rays, a slight potentiating effect was consistently found. The magnitude of potentiation of the radiation effect appeared to depend on the concentration of Bleomycin. When the cells were treated pulsewise at various periods after irradiation, the potentiating effect was found only during the first 2hr. Simultaneous application of X-rays and Bleomycin provided the greatest effect.

View full abstract

Effect of oil-attached BCG cell-wall skeketon (BCG-CWS) on cell-mediated cytotoxicity in tumor-bearing mice was investigated using the allograft system. It was found that the treatment with oil-attached BCG-CWS was able to elevate the immunologically depressed state of tumor-bearing mice to a normal level as determined by chromium release assay.

View full abstract

The effect of combining chemotherapeutics (Mitomycin-C, cyclophosphamide, or 5-fluorouracil) and immunopotentiator (anaerobic Corynebacterium liquefaciens) against Ehrlich ascites carcinoma in mice was examined. Mitomycin-C and cyclophosphamide were given intraperitoneally 2 days after the inoculation of tumor cells. 5-Fluorouracil was administered intraperitoneally for 7 consecutive days beginning from the second day after inoculation of tumor cells. C. liquefaciens was given intraperitoneally in various time regimens before or after the drug. The best prolongation of survival was observed when C. liquefaciens was given after the administration of Mitomycin-C or cyclophosphamide but no effect was seen in the combination of 5-fluorouracil and C. liquefaciens.
These results suggest that non-specific active immunotherapy using C. liquefaciens may be a valuable adjunct to the conventional cytocidal anticnacer chemotherapy with agents such as Mitomycin-C or cyclophosphamide and the most important variable seems to be the time at which the immunopotentiator is given during the therapy.

View full abstract

Percentage of lymphocytes stimulated by phytohaemagglutinin and arrested with Methotrexate at the G1/S boundary of their first cell cycle in vitro was scored using ³H-thymidine and autoradiography. Bleomycin decreased the labelling index more when added to cells nearly arriving at, and residing in, the G1/S point, than if acting during early stages of the DNA synthesis induction.

View full abstract

Examination of the antitumor activity of cationic unsonicated liposomes containing cytosine arabinoside showed that the intraperitoneal administration of the liposome-cytosine arabinoside mixture exerted a markedly enhancing antitumor effect against mouse leukemia L-1210.

View full abstract